I think the internal rust on the slip yoke is an indicator of bad things inside the transmission.
The missing undercoat near the trans end might be from a trans swap. Don't think the drive shaft could have done that unless the previous trans tail shaft exploded.
You could wire wheel the rusty end and then insert it into the trans and check for play.
My guess is the bushing has been damaged from it's removal.
Might not be terminal.
Is this dirt or a crack.
View attachment 1716055794
Is the trans /engine rotated?
View attachment 1716055796
